1. Field of the Invention
The present invention relates to an internal voltage supplier for a memory device, and more particularly to an internal voltage supplier for a memory device which can selectively receive power supply voltages supplied from the interior or exterior of the memory device, so as to provide the selected power supply voltage to the memory device.
2. Description of the Prior Art
As generally known in the art, a memory device operates by using a driving voltage Vdd applied from an exterior thereof. Recently, semiconductor memory devices have shown a tendency of having high integration and using lower power, so that the voltage level of a driving voltage Vdd applied to the memory device becomes lower and lower. However, when the driving voltage of a memory device is lowered, it is required to change the threshold voltage of a transistor, which consequently deteriorates the operation stability of the memory device. Therefore, it is important in a low-power high-integration memory device to provide stable voltage to the memory device. To this end, the conventional memory device uses an internal high-voltage generator, which is contained in the memory device, to provide a high voltage to an internal circuit requiring the high voltage.
However, the conventional memory device has a problem in that it frequently occurs that the voltage level of the high voltage generated from the internal voltage generator greatly changes depending on temperature change or a memory device fabricating process.
Also, in the conventional memory device, when an auto-precharge operation requiring the use of a high voltage is performed, it frequently occurs that the voltage level of the high voltage is temporarily dropped, which would cause a malfunction of the memory device. Such problems occur in other internal voltages of the memory device, too.